Track-laying tractor



C. L. BEST. TRACK LAYING TRACTOR. APPLICATION FILED OCT. 8, 1917.

Patented Oct. 25, 1921.

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C. L. BEST. TRACK LAYING TRACTOR. APPLICATION FILED OCT. 8, 1917.

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C. L. BEST. TRACK LAYING TRACTOR. APPLICATION FILED OCT. 8. 1917.

Patented Oct. 25, 1921.

4 SHEETS-SHEET 4.

UNITED STATES PATENT OFFICE.

CLARENCE LEO BEST, OF OAKLAND, CALIFORNIA, ASSIGNOR TO THE HOLT MAN UFAC- TURING COMPANY, OF STOCKTON, CALIFORNIA, A CORPORATION OF CALIFORNIA.

TRACK-LAYING TRACTOR.

Specification of Letters Patent.

Patented Oct. 25, 1921.

Application filed October 8, 1917. Serial No. 195,440.

To all whom it may concern:

Be it known that I, CLARENCE LEO BEST, a citizen of the United States, residing'at Oakland, in the county of Alameda and State of California, have invented certain new and useful Improvements in Track- Laying Tractors, of which the following is a specification, reference being had therein to the accompanying drawing.

This invention relates to track laying tractors and more particularly to track laying tractors of the type in which the endless tracks are capable of yielding oscillatory movement to automatically accommodate themselves to broken and uneven ground surface.

The object of the invention is to provide an improved tractor of the type referred to made up of a minimum number of parts, to provide improved spring mechanism for resisting upward tilting movement of the endless tracks, to provide improved supporting means for the motor and allied devices, to provide for the embodiment of the motor and allied devices in the form of a strong compact unitary structure, and for an improved connection of the same with the endless tracks and the connect-ion of the endless tracks together whereby a construction is produced that is practically frameless and of an extremely simple and compact nature which will be strong and eflicient in use and can be manufactured very cheaply.

The invention, with other objects and advantages thereof and the particular construction, combination and arrangement of parts comprising the same will be understood from the hereinafter contained detail description when considered in connection with the accompanying drawings forming a part hereof and illustrating a preferred embodiment of the invention.

In the drawings:

Figure 1 is a side elevationof a tractor constructed in accordancewith the present invention.

Fig. 2 is a top plan view. I

Fig. 3 is an end elevation with parts shown in section.

flFig. 4 is a section on the line 44 of Fig. 2, the power shaft and gearing being omitted.

Fig. 5 is a detail top plan view of the supporting member, and

Fig. 6 is a detail side elevation and partial section of the supporting member.

While I have illustrated a special embodiment of the invention in the drawings, I desire it to be understood that changes and obvious modifications of the structure shown, and the embodiment of the invention in other forms, as will appeal to those skilled in the art and within the scope of the appended claims may be practised without departing from the spirit of the invention.

in accordance with the invention, the motor and allied device are all mounted on a single member or part,said part being shaped to form a carrier and housing for the operating mechanism and constituting the main frame of the machine. This preferably takes the form illustrated in the drawings, a hollow casting tapering from front to rear and comprising a central longitudinally extending bottom portion 1 and side portions 2 substantially U-shaped in cross section extending below the lower face of the central bottom portion 1, the side portions 2 being of greatest height at a point 3 intermediate the ends thereof and from thence extending in a gradual curve or incline from said points to the opposite ends of the casting, said U-shaped side portions 2 constituting in effect reinforcing ribs extending the full length of the casting at each side thereof, the structure thus produced affording a very strong support and forming a partial housing for the parts. The upper face of the central bottom portion 1 of the casting is preferably shaped as shown with the spacedraised portions 4 to accommodate the motor and allied devices or parts. 5 designates the motor at the front of the casing shown as an internal combustion engine, 6 the clutch, 7 the change speed transmission, and 8 a pinion loosely mounted on the transverse two part drive shaft 9 supported in bearings 10 at the rear end of the supporting member or casting. 1111 are clutch members adapted to couple the two sections of shaft 9 to the pinion 8, and 12-12 are drive pinions located at the outer ends of the said shaft sections. The motor and allied parts or devices may be of any approved type, and

.I am therefore only indicating in the drawings and describing in a general way one of the well known constructions. The engine and base are preferably formed integral as shown and secured to the supporting member or casting in any suitable way. A casing or cover 13 is detachably connected with the supporting member or casting forming therewith a complete housing for the motor devices located in rear of the motor.

. rear end the bars 16 are provided with a bearing 17 for the axle 14 and rotatably mounted on the axle between the bars is a driving sprocket 18. 19 are securing nuts on the ends of the axle 14. At the forward end of the bars 16 an idler wheel 20 is mounted on a short shaft 21 supported in bearings 22, and trained over the driving sprocket 18 and idler wheel 20 is the endless traction chain 23. The driving sprockets 18 are provided with internal gears 19 with which the driving pinions 12-12 mesh. 25 designates guide rollers for the chain rotatably supportedon the bars 16.

Between the frame or casting and the endless tracks is provided a yielding member which is disposed transversely of the endless tracks and the supporting frame. In the special embodiment of the invention illustrated in the drawings the yielding member takes the form of a leaf spring 26, said spring having its opposite ends engaging housings 27 on the bar 16 of the endless tracks, and the forward end of the supporting frame or casting rests upon the spring intermediate its ends, the supporting frame being formed with a bearing portion to engage the yielding member 26. The bearing portion may be slightly curved as shown to correspond with the normal curvature of the yielding member 26, and the yielding member is preferabl secured to the supporting member by c ips or U-bolts 29.

As will be understood each of the endless tracks are capable of independent yielding oscillatory movement in a vertical plane to independently accommodate itself to varying ground contours. Through the medium of the clutch members 11-11 the endless It will be observed that'the construction hereinbefore described is composed of only three main parts, the supporting member or casting and the pair of endless tracks. The axle forms the means for connecting the supporting member to the endless tracks and also the .endless tracks together. The special spring mechanism provided issimple and eflective. The motor and allied devices are in the form of a strong compact unitary structure, the resulting construction being practically frameless, of an exceedingly simple, compact nature, that will be strong and eflicient in use and can be manufactured very cheaply.

IVhat I claim is:

1. In a vehicle, a main frame comprising a hollow casting tapering from front to rear and having a central longitudinally extending bottom portion" and side portions,

the latter being substantially U-shaped in cross section and constituting in effect reinforcing ribs extending the full length of the frame at each side thereof.

2. In a vehicle, a main frame comprising .a hollow casting tapering from front to rear and having a central longitudinally extending bottom portion and side portions extending below said bottom portion and substantially U-shaped in cross section, said side portions being inclined downwardly from the front end of the main frame to a point intermediate the ends, and thereafter inclining upwardly to the rear end ofsaid main frame.

3. In a vehicle, a main frame comprising a hollow casting having a bottom part and side portions, said side portions being sub: stantially U-shaped in cross section and extending below the bottom part and constituting reinforcing ribs.

In testimony whereof I hereunto -afi'ix my signature in the presence of two witnesses.

CLARENCE LEO BEST. Witnesses:

L. P. MARTIN, H. A. Hansen. 

